Planar substrates charged with pharmaceutically active agents are usefully employed in numerous applications. For example, planar substrates can be formed from plasters charged with pharmaceutically active agents being placed on a support and further covered with a cover layer for purposes of sealing and/or packaging them. These active agent plasters may be embodied in the form of a transdermal system (TDS). These TDSs must be cut to form patches and, therefore, must be cut lengthwise and/or completely apart during their production to arrive at the finished product. Alternatively, plasters charged with pharmaceutically active agents can be formulated without a support layer, wherein parts of the planar substrates charged with pharmaceutically active agents can be separated and can, for example, be taken orally as lozenges.
In the pharmaceutical industry, a TDS may comprise laminates of several layers of different films. The films are often formed in TDSs with adhesives such as acrylates. Additional planar substrates common to the pharmaceutical industry include orally dissolvable films (ODFs) that can be formed in a fashion similar to TDSs. All of these systems must be cut to form the finished product either as a patch or other small form for administration to a patient. TDSs and ODFs are commonly cut to size by means of stamping machines or presses. These stamping machines, which usually cut through the films in a roller mill, press cutting tools against each other at high pressure and thus cleave the film systems that are to be processed. Another application for processing TDSs and OOFs consists of cleaving them with two cutting edges moving in opposite directions, as is the case with shears or knives.
These processes are very limited in their application as they are not capable of producing final products in complex shapes or can do so only at a very high cost. In addition, changing the cutting devices to produce a differently shaped final product is time consuming and each product shape requires a new cutting blade setup or stamping tool. Further, the high mechanical cutting forces involved in cutting TDSs and ODFs with a stamping tool cause high wear on the tool, necessitating frequent and costly replacement. Also, in multilayer TDSs, it is difficult to cut through all of the layers or to selectively cut only the sub-layers of the systems during production.
Devices and methods for cutting planar substrates are well known in the art, such as those described in WO 97/11841. Such devices usually use vacuum suctioning devices in a cutting zone to position the planar substrate in a plane, so that precise cuts can be performed in the desired position. Such devices and/or methods necessitate, however, the use of a vacuum holding device, leading to additional device-related operating and maintenance costs. Additionally, suitable vacuum systems are susceptible to malfunction, since proper operation requires the contact surface of a planar substrate to be positioned precisely over the vacuum suctioning devices so that a seal is formed while maintaining mobility of the substrate at the same time.
Thus, improved methods and apparatus for cutting planar substrates that are simple to configure and are more resistant to malfunctions are highly desired.